Improved methodology for studying diffusion, sorption and desorption in timber fumigation

Abstract

Methods to study movement of fumigant through timber were improved, and procedures were developed that obviated the need for sampling lines. Movement for two fumigants (methyl bromide and carbonyl sulphide) through, and sorption on, heartwood of softwood and hardwood were studied. Each fumigant was sorbed less on softwood than on hardwood and penetrated softwood better than hardwood. Neither fumigant penetrated across the grain. Carbonyl sulphide penetrated timber better than did methyl bromide, and was less sorbed on timber. A rapid method of solvent extraction was developed to enable, rapid estimation of the amount of intact fumigant sorbed in wood. This procedure enabled excellent recovery of methyl bromide as either intact fumigant or as bromide ion.